1. Field of the Invention
The present invention relates to a control device, a control program, and a control method for an observation unit configured to allow samples such as cells to be observed, as well as an observation system.
2. Description of the Related Art
An observation unit of this type includes an observation device configured to enable a sample to be observed to acquire an observation image of the sample, and an illumination device configured to illuminate the sample when the sample is observed with the observation device. Furthermore, the following modes can be selectively set for the observation unit: a search mode for searching for one or more samples for which observation images are to be acquired by an observation device, and an observation mode (hereinafter referred to as a time lapse mode) for using the observation device to repeatedly observe one or more samples for which observation images are to be acquired and acquiring observation images of the samples during each observation.
Here, in the search mode, a user uses the observation device to search for and determine the one or more samples for which observation images are to be acquired. Then, varying sample information for each of the determined samples (for example, the position of the sample, a zoom factor, and a focus position) is recorded in a memory. Furthermore, in the time lapse mode, the one or more samples for which observation images are to be acquired are observed based on the sample information recorded in the memory.
In the aforementioned example of the observation unit, the observation unit is first set to the search mode, and a macro image is acquired which is an observation image of all the samples obtained at a low zoom factor. The user uses the macro image to search for and determine one or more samples for which observation images are to be acquired. Thus, the sample information on the determined samples is recorded in the memory.
Thereafter, the observation unit is set to the time lapse mode. Based on the sample information recorded in the memory, the samples determined by the user are periodically and repeatedly observed with the observation device, with observation images of the samples acquired.
The thus acquired observation images of the samples can be utilized to observe and analyze the culture condition of the samples.
However, regardless of whether the observation unit is set to the search mode or the time lapse mode, during observation, the sample is illuminated by an illumination device in order to enable the observation. Thus, radiation from the illumination device causes heat to be transmitted to the sample. As a result, the temperature of the sample may increase. Furthermore, the observation unit is equipped with, besides the illumination device, a camera, motors, and the like, which serve as heat sources. Hence, the illumination device and conductive heat from these heat sources may increase the temperature of the sample. The increased temperature of the sample is likely to affect the sample, for example, to kill the sample.
Control has been proposed in which in order to reduce the adverse effects of photobleaching and phototoxity on samples such as cells, the illumination device performs an illumination operation only during a part of an observation period for the samples in which the camera performs an image pickup operation. Such control may be also effective when an increase in the temperature of the sample is to be suppressed provided that the control is applied to an observation unit configured to acquire macro images when the search mode is set.
However, the situation to which the control is applicable is limited. If the control is used in various situations, heat from the illumination device may increase the temperature of the sample. Furthermore, the control fails to deal with conductive heat from the heat source.